Wax thread sewing machine



Feb. 11, 1947. Q HAAS 2,415,484

WAX THREAD SEWING MACHINE Filed Nov. 17, 1944 Fatented Feb. 11, 1947 WAX THREAD SEWING MACHENE Otto R. Haas, Beverly, Mass, assignor to United Shoe Machinery Corporation, Flemington, N. 3., a corporation of New Jersey Application November 17, 1944, Serial No. 563,926

6 Claims.

The present invention relates to sewing "machines of the waxed thread type and more particularly to rotary loop takers for hook needle shoe sewing machines in which a portion only of the loop taker engages the thread, the remaining portion being engaged by a driver for the loop taker so arranged as to be out of contact with the thread.

In inventors prior United States Letters Patent No. 2,219,308, granted October 29, 1940, there is disclosed a waxed thread lockstitch sewing machine having a rotary shuttle, composed substantially in its entirety of synthetic resin, which passes bodily through a loop of needle thread during formation of each stitch, the synthetic resin providing thread engaging surfaces which facilitate handling the thread. In the machine for which the patented shuttle is intended to be employed, a driver for the shuttle acts directly on the surfaces of the shuttle, which are also engaged by the thread during passage of a needle loop about the shuttle. To enable passage of the thread along the surfaces of the shuttle engaged by the shuttle driver, there must be a slight spacing of the parts, which is conducive to Wear and noise in operation at high speeds. As soon as the thread engaging surfaces of the shuttle become roughened from wear, the advantages of utilizing synthetic resin are substantially offset by the tendency to abrade the thread.

In certain other sewing machines of this type, loop takers are utilized which do not pass bodily through the loops of needle thread but act to carry each loop about athread case contained therein, the loop of needle thread being supported entirely by a beak on the loop taker from which the needle thread is disengaged after being carried about the thread case. With the use of the latter-mentioned form of loop taker, there is no lost motion required between the loop taker and its driver to provide space for passage of the needle thread between the driver and the loop taker, and also a more compact construction and arrangement for the loop taker and thread case is rendered possible. Thus, a quieter and more durable operating mechanism can be utilized, particularly under conditions of high-speed operation.

The objects of the present invention are, accordingly, to provide a shoe sewing machine with a loop taker in which effective use of synthetic resin thread engaging surfaces may be retained indefinitely while at the same time spacing between the loop taker and the driver is unnecessary and generally to improve the construction and mode of operation of a loop taker'in a lockstitch sewing machine.

The loop taker embodying the features of the present invention, therefore, comprises two portions, one of suitable metal having a configura-' tion to engage and be rotated by the usual form of driver, and the other portion of synthetic resin constructed to open and carry each loop of needle thread about a thread case within the loop taker without itself passing through the needle loop and to shield the metallic portion from contact with the thread during passage of the needle p about the thread case. As illustrated, the machine in which the present loop taker is utilized is provided with e, raceway member for rotatably supporting the loop taker, and the line of division between the resin and metallic portions forms the joint along those surfaces of the loop taker engaged by the raceway member. By locating the joint between the two loop taker portions in this way, full benefit is obtained in facilitating movements of the thread along the synthetic resin surfaces without the possibility of injury to the thread by being abraded on roughened surfaces of the loop taker resulting from impact with the driver for the loop taker or in any other way which interferes with the easy passage of the needle loop about the thread case. The resin surfaces of the loop taker are substantially reinforced by the metallic portion, and the durability of the resin portion as a whole is correspondingly benefited. Preferably, the joint between the two portions of the loop taker is so located that the resin portion extends outside the metallic portion, thus enabling an extremely tight joint to be formed during the curing process of the synthetic resin which tends to contract, increasing the grip of the two portions, one on the other.

These and other features of the invention will be more clearly understood from the following detailed description taken with reference to the accompanying drawing.

In the drawing:

Fig. 1 is a view in right side elevation, partially broken away and in section, of a portion of a sewing machine embodying the features of the present invention;

Fig. 2 is a plan view of the loop taker illustrated in Fig. 1;

Fig. 3 is a sectional view of the loop taker illustrated in Fig. 2, taken along the line III-III; and

Fig. 4 is another sectional view of the loop taker, taken along the line IV-IV of Fig. 2.

The illustrated loop taker is constructed for use in a waxed thread lockstitch shoe sewing machine similar to that disclosed in United States Letters Patent No. 1,169,909, granted February 1, 1916, upon an application filed in the name of Fred Ashworth, and is intended to cooperate with a curved hook needle it and other stitch forming and work feeding devices, more fully described in that patent, to form a lock'stitch seam, a loop of needle thread 12 being indicated in Fig. 1 in an open position assumed during passage about a supply of locking thread it contained in a circular thread case [5 of the usual metallic construction, as illustrated in the patent.

The loop taker of the present invention for opening and carrying loops of needle thread about the thread case has a substantially cylin drical body, two portions l8 and 20 of which serve two relatively distinct purposes, the portion l8 being constructed from steel with a series of external beveled gear teeth out to engage a toothed driver gear (not shown), and the portion 20 being molded from synthetic resin, preferably of the phenolic or urea type base, joined to the driver engaging portion H3. The resin portion 20 is shaped to engage the needle thread loop in the same way as in the all metal loop taker of the patent, with a beak 22 and a grooved guideway 25 within which a flange on the thread case it is rotatably supported. To facilitate opening and carrying each loop of needle thread'about the thread case, the thread case is retained from rotation with the loop taker in the usual way, and one end of the guideway engaging flange on the thread case holds one side of the needle loop while the other side is carried by the beak of the loop taker about the thread case, thus imparting a half twist to the needle loop during its passage. After being carried about the thread case, the loop of needle thread is shed from the loop taker beak 22 without passing about the body of the loop taker and is drawn from the thread case as it is contacted by others of the stitch forming de- In order to avoid the possibility of contact by the needle thread with the steel portion of the loop taker particularly at the joint 25 between the two portions, the exposed edges of the joint are located along the surfaces within a circumferential groove 25 running around the loop taker for receiving a circular guide plate 28 acting as a raceway for the loop taker. The guide plate 28 is secured to the frame of the machine, indicated at 3!), and separates the thread engaging and driver engaging portions of the loop taker, fitting the groove 25 throughout its length. By this construction, there is no possibility of the thread in the needle loop coming into contact with the driver portion or the joint between the loop taker portions and the driver portion, the joint being located outside the path of the needle lo'op While the latter is being acted upon by the loop taker.

To retain the thread case against rotation with the loop taker, as in the machine of the Ashworth patent while at the same time enablingfree'passage of the needle loopabout the thread case it, the thread case is engaged alternately by either one of a pair of reciprocating pins 32 slidingly mounted in a stationary casing 34 for the driver engaging portion of the loop taker. The outer ends of the pins 32 are acted upon by a rattrap spring 36, and the central portions are formed with lateral projections engaging an internal cam surface 38 on the steel or driver engaging portion (8 of the loop taker, which portion includes a roughened and perforated section or sleeve pro- 4 jecting within the resin portion 20 to provide the cam surface 38 which, being of metal, has sufficient area of contact with the projections on the pins 32 to insure durability.

During the molding of the resin portion 29 over the metallic portion 18, in the manufacturing of the loop taker, portions of the material of the resin portion 20 are forced into the perforations in the metallic portion to form rivet-like plugs 46 integral with the resin portion, thus providing a firm joint or secure anchorage between the portions I8 and 20. Consequently the resin portion surrounds and shields the perforated section of the metallic portion axially of the loop taker body so that the periphery or inner edge of the metallic portion cannot be engaged by the thread of the needle loop. Furthermore, due to the characteristics of the synthetic resin employed, there is a tendency for the resin portion 20 to shrink during the curing process, strengthening the joint and providing positive assurance that no slippage or lost motion will occur between the resin and metallic loo-p taker portions.

For convenience in assembling the thread case with the loop taker, the synthetic resin portion 20 of the loop taker is provided with a removable sector 42 including a portion of the guideway 24 secured in position by a series of screws M and a dowel pin 35. The joints between the sector and the remainder of the synthetic resin portion 20 are so arranged that the thread never engages the outer edges of the joints in parallel relation thereto, always moving along the surfaces at an angle to the joints.

With a loop taker constructed in this way, full advantage of the use of synthetic resin thread engaging surfaces for a waxed thread type of shoe sewing machine is obtained so that extremely easy passage of each needle loop about the thread case is rendered possible and a loop taker is provided in which the irregularly shaped surfaces may be formed by a molding process while the regularly shaped toothed driver engaging surfaces may be out man easily performed machine operation separate from the molding operation, thus retaining the strength required for the driver engaging and cam supporting portions of the loop taker without disadvantage to the resin thread engaging portions which necessarily are of somewhat less strength. Also, any injury to the resin thread engaging portion does not render Worthless the entire loop taker body inasmuch as the resin portion may readily be removed from the metallic portion and the metallic portion again utilized in a molding operation to form a new thread engaging portion, As a result, a loop taker is provided which is inexpensively manufactured and economically serviced for use.

The nature and scope of the invention having been indicated, what is claimed is:

1. A waxed thread lockstitch sewing machine, having in combination with other stitch forming devices a locking thread supply case and means for carrying each needle loop about the thread case, comprising a needle thread loop taker acting to open each loop of needle thread for the thread case without itself passing through the needle loop and having a synthetic resin thread engaging portion and a metallic driver engaging portion shielded from contact with the thread by the resin portion.

2. A waxed thread lockstitch sewing machine, having in combination with other'stitch forming devices a locking thread supply case and means for carrying each needle loop about the thread case, comprising a needle thread loop taker acting" to open each loop of needle thread for the thread case Without itself passing through the needle loop and having a synthetic resin thread engageing portion and a metallic driver engaging portion shielded from contact with the thread by the resin portion, and a guide member within which the loop taker rotates, the line of division between the resin portion of the loop taker and the metallic portion forming a joint along the surfaces engaged by the guide member.

3. A waxed thread lockstitch sewing machine, having in combination with other stitch forming devices a locking thread supply case, means within which the thread case is rotatably mounted comprising a needle thread loop taker acting to carry each loop of needle thread about the thread .case without itself passing through the needle loop and having a synthetic resin thread engaging portion and a metallic driver engaging portion formed with a cam surface, and reciprocating pins engaging the cam surface on the metallic portion for retaining the thread case from rotation with the loop taker by alternate engagement with the thread case during rotation of the loop taker.

4. A Waxed thread lockstitch sewing machine, having in combination with other stitch forming devices a locking thread case and means for passing loops of needle thread about the thread case comprising a loop taker acting to open each needle loop for the thread case without itself passing through the needle loop and having a molded synthetic resin thread engaging portion and a metallic driver engaging portion securedi together with a joint comprising a perforated sec-- tion of the metallic portion within the synthetic resin portion, the latter including integral rivetlike plugs extending into the perforations of the metallic portion.

5. A rotary loop taker for use with a waxed thread sewing machine, comprising a circular driver engaging portion of wear-resistant metal, and a thread engaging loop taker portion of synthetic resin firmly joined to the driver engaging portion and arranged to shield the periphery of the driver engaging portion from contact with the thread.

6. A rotary loop taker for use with a waxed thread sewing machine, comprising a circular driver engaging portion of wear-resistantmetal, and a thread engaging loop taker portion of synthetic resin firmly joined to the driver engaging portion and arranged with a circular guideway for receiving a guide member within which the loop taker rotates to shield the driver engaging portion from contact with the thread.

OTTO R. HAASE REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES. PATENTS Number Name Date 1,169,909 AShWOIth Feb. 1, 1916 2,219,308 Haas Oct, 29, 194G 

